First Time Closing - How to blow out main drain, and general methodology check


Jan 12, 2018
Saint Louis
I will be closing my pool this year myself for the first time. I have a new cyclone. My pool has one skimmer and one main drain on the suction side, and on the return side also two lines - one leading to three eyeballs and the other to a lower return. I was hoping to just work from the skimmer. I understand conceptually (I think - someone please correct me if you notice anything amiss) how to get all lines done except the main drain:
- Lower the water level to a couple inches below skimmer
- Set suction side jandy valve for main drain closed, skimmer open
- Set filter to recirculate, unscrew eyeball covers, set return-side jandy valve to eyeball return line open, lower return closed
- Blow out eyeball returns
- Set return-side jandy valve to lower return open, eyeball returns closed
- Blow out lower return. Simultaneously set return jandy to closed to create air lock while immediately turning off cyclone pressure
- But now what about the main drain? The suction side jandy cannot be set to move air straight from skimmer line over to main drain line (understandably). Is the only way to do this to go work from the pump to blow the main drain back?

Appreciate any/all feedback! Thanks.


Bronze Supporter
Jul 14, 2017
Jenkintown, PA
The valve might have more positions than is obvious. On mine, Loosening the screw holding down the handle allows me to manipulate the valve to close off the pump and force air from skimmer to main drain.

Also, I think plugs are usually put on the returns if you can reach them. Although I don’t know a reason an airlock won’t work if your valves allow. Plugs offer some more security